Electrical contact socket



Dec. 21, 1954 F. U'rz 2,697,821

ELECTRICAL CONTACT socxET Filed oct. 7, 1949 i 23 l l l l LJ /M/f/vrae @Fai/CH (/rz United States Patent C l 2,697,821 ELECTRICAL CONTACT SOCKET Friedrich Utz, Obemdorf-Aistaig, Wurttemberg, Germany Application October 7, 1949, Serial No. 120,044 Claims priority, application yGermany April 22, 1949 1 Claim. (Cl. 339-258) The present invention relates to electrical contact sockets provided with longitudinal slits to receive a plug pin for making electrical connections. Special elastic members, usually in the shape of spring rings applied on the outside, have hitherto been attached to the socket tongues in order to press the said socket tongues, produced by the longitudinal slits, elastically against the inserted plugpin and to thereby ensure a good electrical contact.

Apart from the fact that the production becomes more expensive by using and attaching an additional spring member, a perfectly good and tight contact of the contacting surfaces is not necessarily produced by these means.

The object of the present invention is to produce a socket avoiding these disadvantages by making the socket tongues in such a way that the tongues themselves exert an elastic clamping effect. According to the invention this is accomplished by widening or bulging out the base of the socket tongues, produced by the longitudinal slits,-and by slightly bulging them so that they clamp elastically towards each other.

The production of such sockets is a very simple one according to the new production method. The socket tongues are spread out by a press bar which has a thickened head and are then pressed down onto the unthickened part (shaft) of the press bar by pressing tools which move preferably in a direction vertically to the axis of the socket.

Further characteristics of the invention will be set forth in the following description. Especially to be mentioned is the fact that the press device is designed in such a way that the entire shaping of the socket tongues is made by a single operation.

.In the accompanying drawing the new contact socket and the pertinent production device are shown in one example.

Figs. l, 2 and 3 show a socket in various steps of production on an enlarged scale in which Figs. 1 and 2 are longitudinal cross sections and Fig. 3 is a side view of the finished socket.

Fig. 4 is a longitudinal cross section through the middlev of the press device.

The socket consists of a cylindrical bar 1 on which the socket tongues 4 are made by means of a central drill hole 2 and for instance four radial longitudinal slits 3.

The production method may be explained by referring to Figs. 1 to 3. A cylindrical press bar 5, the head 5 of which is slightly enlarged is inserted between the socket tongues 4. Thereby the socket tongues 4 are spread out as shown in Fig. 1. In the shown example the enlarged head 5' of the press bar 5 has a spherical shape (ball point) and the diameter of this sphere is slightly greater than the diameter of the other part (shaft) of the press bar 5.

The socket tongues will be spread out more and more according to the deeper penetration of the press bar 5, 5 until the press bar touches the end of the socket drill hole 2. The spread out socket tongues will then be pressed together, and down onto the press bar 5 by press tools 6 which move from the outside radially and in a direction vertical to the axis of the socket tongues as shown in Fig. 2. By this the socket tongues 4 will be slightly enlarged at their base, indicated at 7 in Fig. 2. At the same time the tongues 4 will be slightly bent at a point indicated at 8 in Fig. 2. After having produced this effect the press tools 6 move outwards and the press bar 5, 5 will be extracted from the socket in an upward- 2,697,821 Patented Dec. 21, 1954 ly direction. The socket tongues 4 have now been shaped as shown in Fig. 3. The tongues 4 touch each other at their upper ends 9 and exert an elastic clamping effect. The slits 3, having had originally parallel sides, have now lzcome wedge shaped tapered from the base to the top It will be understood forthwith that a plug pin inserted between the elastically clamping socket tongues 4 will be elastically embraced and securely held. An arcing as it has been previously experienced and has destroyed the contact surfaces can not occur.

In order to avoid that the socket tongues 4 will be spread out too much by the insertion of the press bar 5, 5 a ring shaped stop is provided to limit the outward movement of the said tongues. This stop will be more fully described in connection with the press device.

According to Fig. 4 the press device consists of a bottom tool and an upper tool. The bottom tool consists of a base plate 10 and a holding and guiding body 11 the centrally drilled hole 12 of which receives the socket 1, 4. The socket 1, 4 is held by a clamping member 14 influenced by a helical compression spring 13 and can be tightened by means of a hand lever 16 designed as an eccentric 15. The clamping member 14 is rotatably connected with the hand lever 16 by a bolt 17.

In order to make it` possible that sockets of different length can be held and worked, interchangeable supports 18, 19 are provided at the bottom of the holding body 11. The support for the lower end of the socket 1 can, of course, be designed in another manner, for instance it could be made adjustable in height.

The upper part 20 of the drill hole 12 has a somewhat greater diameter than the lower part, the walls of which serve as a stop to limit the spreading movement of the socket tongues if a plate 24 is not used. In the example shown in Fig. 4 there are four pressing tools 6 guided in radially extending guides on the upper part of the holding body 11. Each of the said pressing tools 6 has an angular shaped projection 6 extending downwards and is influenced by a helical compression spring 22 arranged in the holding body 11. The said projections 6 of the pressing tools 6 each have at their upper outer edge a Working plane 23, which is either oblique or spherically shaped. In the shown example the pressing tools 6 are covered by a plate 24 which is rigidly connected with the holding body 11. The said plate 24 has a central drill hole 25 the diameter of which is approximately the same as the diameter of the drill hole 20.

The walls of the hole 25 serve as a stop to limit the spreading movement of the socket tongues. The shoulder 24 of the disc 24 is curved downwardly and cooperates with recesses 26 of the pressing tools 6.

The upper tool consists of a body 27 the inner lower part of which has a conically shaped cavity 28. The said body 27 has a central drill hole 29 into which a guide member 30 is threaded. This guide member 30 guides a movable shaft 31 on the lower end of which the press bar 5 is xed. A helical compression spring 32 abutting against a collar 31 of the shaft 31 always presses the shaft 31 downwardly. The said helical compression spring 32 abuts with its upper end against a nut 33 screw threaded into the drill hole 29. By turning the said nut 33 the pressure of the helical spring 32 can be varied.

After having described the various parts of which the press device consists, the operation is as follows:

When the upper and the bottom tool of the press device are separated (for instance the upper tool 27 is lifted) a socket 1, 4 will be inserted in the hole 12 of the holding body 11 and clamped by the eccentric clamping lever 15, 16. The upper tool will then be moved downwards and in connection herewith the press bar 5 with its spherically shaped head 5 will be inserted between the socket tongues 4 and will spread them outwardly. The outwardly spread tongues 4 contact the wall of the drill hole 25 of the cover plate 24 so that the upper part of the tongues 4 are prevented from spreading out further. The strength of the helical spring 32 is so great that it will not be compressed before the press bar 5 has come to rest at the bottom of the socket drill hole 2. From this moment on the press bar 5 will stop its downwards movement while the body 27 continues to move downwards. The oblique or spherically shaped planes` 23 of the pressing tools 6 touch against, and glide on, the inner cone 28 and will, therefore, be pressed radially iuwards by the downward movement of the body 27. In this way theV spread out socket tongues 41wil1 be compressed again and pressed down onto the press bar 5i.

The operation is thus finished. The body 2'7v moves up again, the clamping tools 6 will be pushed outwardly by the springs 22 and the pressV bar will be extracted out of the socket. The nished shaped socket willl be removed from the holding body 11 and replaced by another unnished one, and a new operation can begin.

I claim as my invention:

Electrical contact socket for receiving a cylindrical insertable rod comprising a cylindrical bar, anda plurality of tongues each having a free end and a base endy and being integral with the bar at the base'endof each tongue. and separated by longitudinal slits, the tongues being arranged adjacent each other in an annular arrangement and each tongue bulging slightly outwardly at the base in a radial direction as a curved portion and projecting slightlyinwardly to a point just beyond the bulge and then sloping in a gradual direction to the free end of each tongue, each slit being approximately elongatedv V-shaped with the apex of the V at the free ends of two adjacent tongues and the open part of the V at the base endof two adjacent tongues formed by the two adjacent tongues bulging slightly outwardlyl and then inwardly', and said tongues each having a spring action at its free end due to the bulge at the base and the inwardly directed free end of the tongue to resiliently grip the rod by means of the free ends of the tongues.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 340,065 Stupakot Apr. 13, 1886 969,787 Leppert Sept. 13, 1910 1,104,720 Turner Iuly 21, 1914 1,900,099 Ferguson Mar. 7, 1933 1,973,890 Torrnyn et al Sept. 18, 1934 2,007,848 Cromartie July 9, 1935 2,339,146 Carlisle et al. Jan. 11, 1944 2,366,269 Lawson Ian. 2, 1945 2,415,404 Baller Feb. 11, 1947 FOREIGN PATENTS Number Country Date 443,968 Germany Oct. 9, 1925 496,636 Great Britain Dec. 2, 1938v 

